Leak detection method taking altitude adjustments into account

Abstract

The invention relates to a method for detecting a leakage of at least one air spring (100) of a vehicle (200), the vehicle (200) comprising: - at least one air spring (100) comprising a height sensor (10), the method comprising - measuring (110), at a first measuring time (t1, t2), a first height (h1) of the air spring (100) by the height sensor (10), - measuring (120), at a second measuring time (t2, t3), a second height (h2) of the air spring (100) by the height sensor (10), wherein the second measuring time (t2, t3) has a measuring time interval (Δt_mess) to the first measuring time (t1, t2), wherein the measuring time interval (Δt_mess) has at least one height adjustment-free time interval (Δt12) or a height adjustment-dependent time interval (Δt23), - determining (130) an actual change in height (Δh_ist) as a function of the first height (h1) and the second height (h2), - Determining (140) a leakage of the at least one air spring (100) as a function of the actual height change (Δh_ist) and the first measuring time (t1, t2).

Description

[0001] The invention relates to a method for detecting a leakage of at least one air spring according to the independent method claim, a corresponding air spring, a corresponding computer program product, a computer-readable data carrier, a control unit for carrying out the method and a corresponding vehicle with a corresponding control unit.

[0002] Vehicles with air springs are known, whereby the height of an air spring, in particular “how low” the vehicle or the air spring is, can be adjustable. A vehicle can, for example, have at least one air spring, for example one air spring per wheel. The height (in particular length) of an air spring can be adjusted using compressed air. For example, the air spring can be pressurized with compressed air to increase the height. Alternatively, compressed air can be released from the air spring to reduce the height. It can also be provided that the air spring, a pressure accumulator (e.g. for compressed air) and / or a connecting line (in between) has a leak. This can cause air or pressure to (unintentionally) escape and / or be reduced.

[0003] The state of the art has disadvantages. For example, the detection of a leak is not possible or only inadequate. For example, the accuracy and / or reliability of leak detection may be insufficient. Furthermore, it may be that an (unnecessary) amount of information, in particular sensors and / or sensor data, is required. Furthermore, it may be that the detection of a leak and / or the compensation of pressure losses is (only) possible by using several / all control units and / or when starting the engine. Furthermore, changes in temperature are not taken into account in known methods and / or systems. This can lead to an incorrect assessment of the pressure and / or volume. This can reduce accuracy. A "tilted position" of the vehicle, in particular due to different heights (e.g.The resulting leakage (due to leakage) of different air springs cannot be compensated for, or can only be compensated for inadequately, in state-of-the-art vehicles, systems, and / or methods. Furthermore, the detection and / or compensation of a leak, particularly during operation, e.g., driving the vehicle, may be inadequate.

[0004] It is therefore an object of the present invention to at least partially overcome at least one of the disadvantages described above. In particular, the object of the invention is to provide an improved method for detecting a leak in at least one air spring. Furthermore, it may be an object to improve safety, handling, roadholding, appearance, and / or confidence in the vehicle. Furthermore, it may be an object to ensure improved utilization of information, particularly during periods with and / or without altitude adjustments.

[0005] The above object is achieved by a method for detecting a leak in at least one air spring according to the independent method claim, an air spring according to the independent device claim, a computer program product having the features of the independent computer program product claim, a computer-readable data carrier having the features of the independent patent claim relating to a computer-readable data carrier, a control unit having the features of the independent patent claim relating to a control unit, and a vehicle having the features of the independent vehicle claim. Further features and details of the invention emerge from the subclaims, the description, and the drawings.In this case, features and details which are described in connection with the method according to the invention naturally also apply in connection with the computer program product according to the invention and / or in connection with the computer-readable data carrier according to the invention and / or in connection with the control unit according to the invention and / or in connection with the vehicle according to the invention and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is or can always be made to each other.

[0006] In particular, advantages described in the context of the first, second, third, fourth, and / or fifth aspect also apply to the first, second, third, fourth, and / or fifth aspect.

[0007] The above object is achieved according to a first aspect by a method for detecting a leakage of at least one air spring, in particular according to the second aspect, of a vehicle (e.g. according to the sixth aspect), the vehicle comprising: - at least one air spring comprising a height sensor, - preferably a control unit, the method comprising - (first) measuring, at a first measuring time, a first height of the air spring by the height sensor (set up for this purpose), - (second) measuring, at a second measuring time, a second height of the air spring by the height sensor, wherein the second measuring time has a measuring time interval to the first measuring time, wherein the measuring time interval has at least one height adjustment-free time interval or a height adjustment-dependent time interval, - Determining an actual (actual) height change depending on the first height and the second height, - Determining a leakage of at least one air spring, depending on the actual height change, and the first measurement time.

[0008] The method according to the first aspect can be computer-implemented and / or performed repeatedly. Preferably, the method can be performed during, before, and / or (preferably) during operation or use of the vehicle, for example, while driving. Alternatively or additionally, the method can be performed at (regular) intervals, for example, every three hours (see below). The control unit can implement the method, in particular where appropriate, for example by controlling the sensors, the air spring, a pressure accumulator, and / or a compressor.

[0009] Preferably, the method is designed to detect a leakage of the at least one air spring, a pressure accumulator and / or at least one connecting line (between).

[0010] The vehicle can have at least one air spring, in particular four air springs (e.g. for each wheel or in each "corner" of the vehicle). It can be provided that the at least one or each air spring can be or is connected (reversibly) to a pressure accumulator and / or a compressor for pressurizing or releasing compressed air. Accordingly, the pressure in the at least one air spring can be adjusted via the pressure accumulator and / or compressor. The pressure accumulator preferably has a (constant) volume. For example, it can be rigidly constructed, e.g. from steel.

[0011] The at least one air spring can have a height sensor. The height sensor can be configured to measure the height (or length) of the air spring. It can be provided that the height is lower at lower pressure. It can be provided that the height is greater at higher pressure. It can be provided that the height sensor is connected to a (or the) control unit, for example via a data connection, whereby in particular data can be transmitted from the sensor to the control unit (in particular in order to store it) and / or the control unit can control the sensor, for example in order to carry out a measurement.

[0012] The (first) measurement can be carried out at a first measuring time. A first height of the air spring can be determined by the height sensor (set up for this purpose). The first height can be specific to the first measuring time, e.g. a first or second time. Preferably, the first height and / or the first measuring time (as well as any further information) can be stored by the control unit, for example in a memory unit of the control unit. It can be provided that this is loaded at a later (in particular a second or further) time. It can be provided that the first height is greater than the second height, in particular since a drop in pressure may be more likely and / or a (potentially existing) leak can lead to a pressure loss. However, it can also be provided that the opposite case occurs in certain constellations.The first measurement time may include a wake-up, (re)start, switching on, and / or unlocking of the vehicle. Preferably, the first measurement time may include (or during) operation, in particular driving, of the vehicle.

[0013] The (second) measurement can be carried out at a second measuring time. A second height of the air spring can be determined by the height sensor (set up for this purpose). The second height can be specific to the second measuring time, e.g. a second or third time. Preferably, the second height and / or the second measuring time (as well as any further information) can be stored by the control unit, for example in a memory unit of the control unit. It can be provided that this is loaded at a later (in particular a second or further) time. It can be provided that the second height is lower than the first height, in particular since a drop in pressure may be more likely and / or a (potentially existing) leak can lead to a pressure loss. However, it can also be provided that the opposite case occurs in certain constellations.The second measurement time may include the vehicle going to sleep, stopping, turning off, and / or locking. Preferably, the second measurement time may include (or during) operation, in particular driving, of the vehicle.

[0014] Preferably, the first and second heights differ. Provision can be made for the method to be aborted or (later) restarted if no difference exists. The first and / or second heights can be configured or changed depending on a leak, a temperature (change), and / or pressure change. The method (in particular the control unit) is preferably configured to detect a leak.

[0015] In this case, a height adjustment can be carried out. A height adjustment can comprise height regulation and / or height control. The at least one air spring can be pressurized with (compressed) air, in particular in order to change the height, preferably to increase it. This can be achieved, for example, by the compressor and / or the pressure accumulator, which are preferably controlled by the control unit for this purpose, e.g. by a control signal from a corresponding valve. This can be used to compensate for a reduced height, in particular due to a leak, another pressure change or pressure loss and / or a temperature change. In this case, a height adjustment can be carried out automatically (e.g. by the control unit) and / or manually (e.g. by the driver via an input device, in particular due to a different desired spring hardness).

[0016] A time interval can (generally) comprise the period of time between two points in time, e.g. between a first / second and a second / third point in time, in particular comprising (or not comprising) the first / second or second / third point in time.

[0017] A height adjustment-free time interval can comprise a time interval in which preferably no height adjustment is performed. This can advantageously comprise a (pure) change in height due to leaks, pressure changes, and / or temperature changes. Advantageously, leaks can therefore be better detected over a height adjustment-free time interval. Furthermore, a height adjustment-free time interval can be (relatively) easy to determine and / or have a long period of time, which can in particular enable improved and / or more stable determination. Advantageously, more frequent and / or regular measuring and / or determination can thus be carried out (e.g., compared to time intervals subject to height adjustment), in particular since or when height adjustment-free time intervals are used ("higher calculation rate").It can be provided that an altitude adjustment-free time interval has a first point in time, in particular as a start time, and / or has or no longer has a second point in time, in particular as an end time. Alternatively, it can be provided that an altitude adjustment-free time interval lies (exactly) between a first point in time and a second point in time. An altitude adjustment-free time interval can have a length between 0.1 seconds and 1000 hours, in particular between 1 second and 100 hours, for example between 5 seconds and 10 hours, preferably between 30 seconds and 1 hour, particularly preferably between 2 minutes and 30 minutes, ideally between 4 and 15 minutes. An altitude adjustment-free time interval can be configured depending on manually or automatically performed altitude adjustment(s).

[0018] A time interval subject to altitude adjustment can have a time interval in which preferably at least one altitude adjustment is carried out. It can be provided that a time interval subject to altitude adjustment has a second point in time, in particular as a start time, and a third point in time, in particular as an end time. Alternatively, it can be provided that a time interval subject to altitude adjustment lies (exactly) between a second point in time and a third point in time. A time interval subject to altitude adjustment can have a length between 0.01 seconds and 10 hours, in particular between 0.1 seconds and 1 hour, for example between 0.3 seconds and 10 minutes, preferably between 0.5 seconds and 2 minutes, particularly preferably between 0.7 seconds and 30 seconds, ideally between 1 and 5 seconds.

[0019] The determination of a leak in the at least one air spring, in particular by the control unit, as a function of the first height, the second height, the first measurement time, the second measurement time, and / or the first / second / third time, can be based at least on these (aforementioned) variables. Preferably, precisely these variables can be measured and / or no further variables can be known or measured. Particularly preferably, the determination can be carried out without measuring a temperature and / or a pressure. Preferably, the determination of a leak can be carried out by comparison, in particular as a function of the first and second measurement times, for example by comparing the first height with the second height, and / or variables derived from these variables.

[0020] It can be provided that the detection of a leak is carried out depending on repeated execution of the method. For example, the method can be carried out repeatedly over an observation period. For example, the observation period can be between 60 seconds and 10,000 days, in particular between 30 minutes and 1,000 days, for example between 1 hour and 365 days, preferably between 6 hours and 100 days, particularly preferably between 1 day and 50 days, ideally between 3 to 30 days. Alternatively or additionally, the observation period can be dependent on the mileage of the vehicle. For example, a mileage can be between 1 km and 1,000,000 km, in particular between 10 km and 10,000 km, for example between 50 km and 5,000 km, preferably between 100 km and 1,000 km, particularly preferably between 300 km and 800 km.It may be particularly preferred to determine a leak as a function of a (repeatedly) determined leak rate, wherein the leak rate can be observed, for example, as a function of the observation period and / or the mileage. In the event of a (larger or increasing) leak, the leak rate of the at least one air spring can, for example, (substantially) increase, in particular over an observation period and / or a mileage. It can be provided that the determination of a leak by the control unit includes detecting an exceedance of a leak rate limit value.

[0021] For example, a leakage velocity limit value can be between 0.01 mm / h and 1000 mm / h, in particular between 0.1 mm / h and 100 mm / h, for example between 1 mm / h and 50 mm / h, preferably between 2 mm / h and 20 mm / h, particularly preferably between 3 mm / h and 10 mm / h, ideally between 5 mm / h and 7 mm / h. If, for example, a leakage velocity limit value of 5 mm / h is exceeded, in particular repeatedly, the control unit or a backend (to which the information can be transmitted) can detect a leak in at least one air spring.

[0022] It can be provided that the first height, the second height, the actual height change, and / or the leakage rate are subjected to filtering, in particular temporal filtering, smoothing, and / or (dynamic) compensation, for example by the control unit and / or the backend. This allows outliers to be compensated and / or the determination to be stabilized or made more robust. This can (among other things) prevent a leak from being detected even though no leakage actually exists.

[0023] Within the scope of the invention, it may be advantageous that during or after the (first) measurement, the control unit carries out: - Controlling by the control unit of the height sensor to transmit the first height and / or the first measurement time to the control unit and / or a backend, in particular to store this in a memory unit of the control unit and / or the backend, in particular comprising a first measurement time, e.g. a first or second time (as a timestamp), at which the measurement is carried out.

[0024] Within the scope of the invention, it is conceivable that during or after the (second) measurement, the control unit carries out: - Controlling by the control unit of the height sensor to transmit the second height and / or the second measurement time to the control unit and / or a backend, in particular to store this in a memory unit of the control unit and / or the backend, in particular comprising a second measurement time, e.g. a second or third time (as a timestamp), at which the measurement is carried out.

[0025] Within the scope of the invention, it can be provided that the determination comprises loading, by the control unit and / or the backend, the first altitude, the second altitude, the first measurement time, the second measurement time, and / or the first / second / third time, in particular from a memory unit of the control unit and / or the backend, preferably into a computing unit of the control unit and / or the backend. It can also be provided to load further (comparison) data. For example, (stored or historical) expected altitude changes, actual altitude changes, and / or leakage velocities can be loaded.

[0026] Within the scope of the invention, it may be advantageous that the determination is carried out as a function of the altitude adjustment-free time interval, wherein in particular the altitude adjustment-free time interval begins or ends with the first measurement time.

[0027] Particularly preferably, a time interval (or the one without altitude adjustment) is (always) used for the determination, preferably for calculating a leakage rate (e.g., in the denominator). This can be advantageous because no (potentially disturbing and / or distorting) altitude adjustment can be included. In other words, a determination can be performed depending on a time interval that lies "outside" of altitude adjustments.

[0028] Within the scope of the invention, it is conceivable that the first measuring time has a first time and the second measuring time has a second time, or that the first measuring time has a second time and the second measuring time has a third time.

[0029] In other words, it can be provided that a (first) measurement is carried out at a first point in time. Preferably, a (second) measurement can then be carried out at a further point in time (then) at a second point in time. Alternatively or additionally, it can be provided that a (first) measurement is carried out at a second point in time. Preferably, a (second) measurement can then be carried out at a further point in time (then) at a third point in time. Accordingly, the first and the second height can be measured at successive points in time, preferably either at the beginning or end of a time interval without height adjustment or of a time interval with height adjustment.

[0030] The second point in time can preferably be later than the first point in time. The third point in time can preferably be later than the first point in time and / or the second point in time. The first, second, and third points in time preferably follow one another.

[0031] It can be provided within the scope of the invention that the determination of an actual height change Δh_ist as a function of the first height and the second height is carried out by forming the difference between the second height h2 and the first height h1.

[0032] Accordingly, it can be calculated and / or valid (equation 1): Δh_ist=h2−h1

[0033] The actual altitude change, particularly in the case of a (first) measurement at a first point in time and a (second) measurement at a second point in time, can be specific to a decrease, preferably over a time interval without altitude adjustment. Alternatively, the actual altitude change, particularly in the case of a (first) measurement at a second point in time and a (second) measurement at a third point in time, can be specific to an increase in altitude, preferably over a time interval with altitude adjustment.

[0034] It is further conceivable that the first measuring time comprises a termination of a height adjustment, wherein a height adjustment is configured to adjust a height of the at least one air spring, for example to a zero level, and wherein preferably the second measuring time comprises a second time at which preferably a height adjustment begins (or has just not yet begun).

[0035] A zero level can have a (desired) height, which should be assumed by at least one other air spring, preferably by all air springs. This can be specific to the front axle and / or rear axle. Preferably, a vehicle assumes a specific position at the zero level; for example, it can then be parked (as upright as possible). Other positions, such as particularly "low" (especially for sporty driving) or "high" for rough terrain, are also conceivable.

[0036] It is also conceivable that the second measuring time has a measuring time interval from the first measuring time, wherein the measuring time interval has at least one altitude adjustment-free time interval, in particular from a first time to a second time, and at least one altitude adjustment-related time interval, in particular from a second time to a third time, wherein in particular the second measuring time has a third time, which in particular has a termination of an altitude adjustment.

[0037] The measurement interval can be the period between the (first and second) measurements. This advantageously allows for more frequent and / or regular measurements and / or determinations, especially if altitude-adjustment-free time intervals are used ("higher calculation rate").

[0038] The (respective) time intervals can contain the first, second, and / or third point in time or no longer contain them (see above).

[0039] Within the scope of the invention, it is optionally possible for the method to be designed to be carried out during operation of the vehicle.

[0040] The vehicle can preferably move during operation, in particular, drive. This can cause the vehicle to tilt, for example, due to a leak. The method can preferably detect and / or (subsequently) compensate for a leak. This can prevent or compensate for tilt and / or unfavorable balancing. This can advantageously reduce wear, lower maintenance costs, improve the driving feel, improve roadholding, and / or improve safety.

[0041] Furthermore, it can be provided within the scope of the invention that the determination comprises a comparison, in particular a difference formation, between an expected change in altitude and the actual change in altitude, wherein in particular - a determination that there is no leakage is made if the comparison shows no deviation or a deviation below a height limit value between the actual height change Δh_ist and the expected height change Δh_erw, in particular Δh_ist - Δh_erw ≤ h_grenz, whereby in this case in particular a leakage speed (see below) of v = 0 mm is assumed and / or can be expected (e.g. when smoothing), - a leak is detected when the comparison shows a deviation above a height limit between the actual height change and the expected height change.

[0042] The height limit can be 0 mm, for example. It can be provided that a determination of whether a leak is present (or not) is carried out individually for each air spring. For example, for a vehicle, this can preferably be carried out for each of at least one, at least two, preferably four, air springs, in particular for "every corner" of the vehicle. If a (sufficient) difference is detected, a height adjustment can be carried out, for example.

[0043] In this case, an expected height change can be stored in the control unit, in particular in a memory unit. This can, for example, comprise a height change that occurred under similar or identical conditions, e.g., a historical height change. It can be provided that this is or was transmitted to the control unit via a data connection, e.g., the Internet, for example, from a backend (of the manufacturer) and / or a cloud. It can be particularly preferred if an expected height change comprises an actual height change of at least one other, in particular (presumably) intact, air spring. In this case, it can be particularly preferred to use the minimal / smallest actual height change of the air springs as the expected height change.

[0044] With regard to the present invention, it may be particularly preferred that the determination comprises calculating a leakage velocity, wherein in particular the leakage velocity is calculated by dividing the actual altitude change by the measurement time interval or (particularly preferably) an altitude adjustment-free time interval.

[0045] It can therefore be provided that the leakage velocity v is calculable and / or defined (equation 2.1): v=Δh_actualΔt_measured

[0046] Here, h_ist can represent the actual elevation change and / or the Δt_mess measurement time interval. The measurement time interval can be (essentially) identical to a height-adjustment-free time interval Δt12, particularly if a (first) measurement is taken at a first time t1 and a (second) measurement at a second time t2. Accordingly, the leakage velocity v can be calculated and / or defined (Equation 2.2): v=Δh_istΔt12

[0047] For example, an actual change in altitude Δh ist = 7 mm (for example, due to a height adjustment between the second time and the third time, or alternatively due to a subsidence between the first time and the second time). For example, a measurement time interval Δt mess= 5 min, and / or a height adjustment-free time interval Δt12 = 5 min. Thus, for example, a leakage velocity v can result: v=7 mm5 min*60 minh=84mmh

[0048] It can also be provided that the measurement time interval is not identical to a height adjustment-free time interval, in particular if a (first) measurement is taken at a second time and a (second) measurement is taken at a third time. Preferably (in this case), the leakage rate can (nevertheless preferably) be calculable as a function of a height adjustment-free time interval, in particular according to equation 2.2. This can advantageously enable a more stable calculation and / or reduce the influence of (potentially disruptive) height adjustment(s).

[0049] It can preferably be provided that the calculation of a leakage velocity is (only) carried out when an actual height change Δh_ist is determined, in particular when Δh ist ≠ 0. Alternatively or additionally, the leakage rate calculation can be performed (only) when a height adjustment is performed. In this case, the leakage rate (for the corresponding air spring) can be set to 0 mm / h. This can save computing power and / or enable a more stable determination.

[0050] Preferably, the leakage rate can be determined independently of a temperature (change) and / or pressure (change). Preferably, the determination of the leakage rate is (only) dependent on a leakage-related drop and / or the time interval.

[0051] Furthermore, it is conceivable that the determination of a leakage of the at least one air spring comprises a comparison comprising - Detecting a leak when a leakage velocity limit has been exceeded, in particular by a leakage velocity, - Determine that there is no leakage if a leakage velocity limit has not been exceeded, in particular if a leakage velocity is less than or equal to the leakage velocity limit.

[0052] This makes it possible to determine whether there is a (relatively) rapid drop or a (large) loss of air from at least one air spring. A loss of air or pressure can be compensated (to a limited extent) by a compressor (e.g., by further supplying compressed air). Advantageously, it can be detected whether a drop or leak has already progressed so far that it can no longer be compensated or will soon no longer be compensated. In this case, a warning message can be issued, for example, to prompt the driver to visit a workshop. A warning message can be issued to a driver via the vehicle, in particular a display device, and / or a mobile device of the driver, for example, a smartphone, a smartwatch, a computer and / or a vehicle key. A leakage speed limit value (in particular, an upper limit for the leakage speed) can be set, for example, in the control unit (e.g.,The backend can be connected to the control unit (for data communication) via a data connection, e.g., the Internet. If an exceedance of this leakage rate limit is detected, particularly by the control unit and / or the backend, this can trigger the output of a warning message (by the control unit).

[0053] It can be provided that, in particular when the method is carried out repeatedly, different values ​​for the leakage velocity and / or for the actual change in height are smoothed, in particular by the control unit and / or the backend. The smoothing can comprise (temporal) averaging, in particular to compensate for outliers and / or incorrect measurements. In this case, an average value for a number of measurements (e.g. simply repeating the method) can be between 2 and 10,000, in particular between 3 and 1,000, for example between 5 and 100, preferably between 8 and 64, particularly preferably between 10 and 48, ideally between 12 and 32. This can enable more stable behavior, increased reliability and / or improved detection. Smoothing can preferably be carried out by the control unit and / or the backend.The control unit and / or (preferably) the backend can (comparatively) detect a leak more quickly and / or earlier. Alternatively or additionally, the smoothing can take place in a backend connected to the control unit. It can be provided that smoothing is (only) carried out if at least one leak is detected, in particular for at least one air spring. If, for example, no leak was detected in at least one or all of the other air springs, the leakage velocity can preferably be assumed to be v = 0 mm, which can be used in particular for smoothing. This preferably makes it possible to achieve a more stable result. In particular, it can be determined more reliably (in particular over an observation period) whether a leak (actually) exists. This makes it possible to compensate for outliers.

[0054] It can be provided that the detection of a leak (or the above-mentioned steps), in particular the comparison of the actual and expected altitude change and / or the verification of the altitude limit and / or the leak speed limit, is performed in the control unit. Alternatively or additionally, it can (preferably) be provided that this is performed in the backend (in particular the manufacturer's). This allows for an improved comparison with identical vehicles and / or an entire vehicle fleet. Thus, a more robust and / or reliable detection of a leak can be achieved.

[0055] The above object is achieved according to a second aspect by an air spring according to the invention for a vehicle, wherein the air spring is designed to implement the method according to the first aspect, in particular in cooperation with a vehicle.

[0056] The at least one air spring can be connected to a pressure accumulator and / or a compressor. It can (also) be provided that the compressor is connected to the pressure accumulator. The compressor can increase and / or decrease the pressure in the pressure accumulator and / or the at least one air spring. It can be provided that the at least one air spring is connected to the pressure accumulator via a line and / or a valve. Accordingly, the pressure accumulator can be (reversibly) decoupled from the at least one air spring. The volume of the pressure accumulator can be constant or kept constant, in particular between a first and a second point in time.

[0057] This results in the same advantages with regard to an air spring according to the invention according to the second aspect as have already been described with regard to a method according to the invention according to the first aspect.

[0058] The above object is achieved according to a third aspect by a computer program product according to the invention, comprising instructions which, when the computer program product is executed by a computer, cause the computer to implement the method according to the first aspect.

[0059] This results in the same advantages with regard to a computer program product according to the invention according to the third aspect as have already been described with regard to a method according to the invention according to the first aspect and / or an air spring according to the invention according to the second aspect.

[0060] The above object is achieved according to a fourth aspect by a computer-readable data carrier according to the invention in which instructions are stored which, when executed by a computer, cause the computer to carry out the method according to the first aspect.

[0061] Thus, with regard to a computer-readable data carrier according to the invention according to the fourth aspect, the same advantages arise as have already been described with regard to a method according to the invention according to the first aspect and / or an air spring according to the invention according to the second aspect and / or a computer program product according to the invention according to the third aspect.

[0062] The above object is achieved according to a fifth aspect by a control unit according to the invention, comprising a computing unit and a memory unit in which instructions are stored which, when at least partially executed by the computing unit, carry out a method according to the first aspect.

[0063] It can be provided that the control unit is designed as a main control device, which is in particular connected to further, second and / or other control units. In this case, the control unit can be activated first ("wake up"), in particular upon start-up, wake-up, unlocking, a first measurement time and / or a second measurement time, while further control units are preferably inactive, in particular until the control unit has performed a height adjustment of the at least one air spring. Accordingly, the control unit can (quickly) compensate for different heights of different air springs. Alternatively or additionally, the control unit can be configured to carry out the method and / or a height adjustment, in particular a level adjustment of different air springs, preferably to a (substantially) identical height, while the vehicle is operating, in particular while driving.

[0064] This results in the same advantages with regard to a control unit according to the invention according to the fifth aspect as have already been described with regard to a method according to the invention according to the first aspect and / or an air spring according to the invention according to the second aspect and / or a computer program product according to the invention according to the third aspect and / or a computer-readable data carrier according to the invention according to the fourth aspect.

[0065] The above object is achieved according to a sixth aspect by a vehicle according to the invention comprising a control unit according to the fifth aspect and / or at least one air spring according to the second aspect.

[0066] The vehicle preferably comprises at least one air spring, preferably four air springs, in particular for each wheel. The vehicle preferably comprises four wheels. The vehicle can therefore stand upright, in particular with respect to a longitudinal axis and / or transverse axis, by having different air springs of (as much as possible) the same height. The control unit can be configured to perform or achieve a level adjustment or level control or "upright" of the vehicle, in particular by the method according to the first aspect.

[0067] This results in the same advantages with regard to a vehicle according to the invention according to the sixth aspect as have already been described with regard to a method according to the invention according to the first aspect and / or an air spring according to the invention according to the second aspect and / or a computer program product according to the invention according to the third aspect and / or a computer-readable data carrier according to the invention according to the fourth aspect and / or a control unit according to the invention according to the fifth aspect.

[0068] Further advantages, features, and details of the invention will become apparent from the following description, in which several embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. In the drawings: Fig. 1 a procedure Fig. 2 a vehicle Fig. 3 a leakage rate. Fig. 4 a height of an air spring over time Fig. 5 a height of an air spring over time

[0069] In the following figures, identical reference numerals are used for the same technical features, even for different embodiments.

[0070] Fig. 1 shows a method for detecting a leak of at least one air spring 100 of a vehicle 200, the vehicle 200 comprising: - at least one air spring 100 comprising a height sensor 10, the method comprising - Measuring 110, at a first measuring time t1, t2, a first height h1 of the air spring 100 by the height sensor 10, - Measuring 120, at a second measuring time t2, t3, a second height h2 of the air spring 100 by the height sensor 10, wherein the second measuring time t2, t3 has a measuring time interval Δt_mess to the first measuring time t1, t2, wherein the measuring time interval Δt_mess has at least one height adjustment-free time interval Δt12 or a height adjustment-dependent time interval Δt23, - Determining 130 an actual height change Δh_ist as a function of the first height h1 and the second height h2, - Determining 140 a leakage of the at least one air spring 100, depending on the actual height change Δh_ist, and the first measuring time t1, t2.

[0071] It can be provided that the determination 140 is carried out as a function of the altitude adjustment-free time interval Δt12, wherein in particular the altitude adjustment-free time interval Δt12 begins or ends with the first measuring time t1, t2.

[0072] Furthermore, it can be provided that the first measuring time t1, t2 has a first time t1 and the second measuring time t2, t3 has a second time t2, or that the first measuring time t1, t2 has a second time t2 and the second measuring time t2, t3 has a third time t3.

[0073] In addition, it is conceivable that the determination 130 of an actual height change Δh_ist as a function of the first height h1 and the second height h2 is carried out by forming the difference 131 between the second height h2 and the first height h1.

[0074] It is also conceivable that the determination 140 comprises a comparison 142, in particular a difference formation 143, between an expected height change Δh_erw and the actual height change Δh_ist, wherein in particular - a determination 144 that there is no leakage occurs if the comparison 142 shows no deviation or a deviation below a height limit value h_limit between the actual height change Δh_actual and the expected height change Δh_expected, - a leak is detected 145 if the comparison 142 shows a deviation above a height limit value h_grenz between the actual height change Δh_ist and the expected height change Δh_erw.

[0075] It may be that the determination 140 comprises a calculation 150 of a leakage velocity v, wherein in particular the leakage velocity v is calculated by dividing the actual height change Δh_ist by the measurement time interval Δt_mess or a height adjustment-free time interval Δt12.

[0076] In addition, it is conceivable that the determination 140 of a leakage of the at least one air spring 100 comprises a comparison 151 comprising - Detecting 152 a leak if a leakage velocity limit value v_limit has been exceeded, in particular by a leakage velocity v, - Determine 153 that there is no leakage if a leakage velocity limit value v_limit has not been exceeded, in particular if a leakage velocity v is less than or equal to the leakage velocity limit value v_limit.

[0077] Fig. 2 shows a vehicle 200 with at least one air spring 100. This is arranged, for example, on the rear axle. By way of example, a further air spring 100 is arranged on the front axle. The at least one air spring 100 has a height sensor 10, which is configured to measure a (first and / or second) height h1, h2. The at least one air spring can be connected to a pressure accumulator, in particular via lines (such as pipes or hoses). The vehicle 200 additionally comprises a control unit ECU having a computing unit CU and a memory unit MU. The control unit ECU can be connected to the height sensor 10 and / or a backend, for example via a (respective) data connection. This allows (measurement) data to be exchanged and / or control to take place.The first height h1, in particular at a first measuring time t1, t2, may preferably differ from a second height h2, in particular at a second measuring time t2, t3, preferably the second height h2 may be lower than the first height h1 (lowering of the air spring).

[0078] Fig. 3 shows a leakage velocity v (y-axis), exemplified as a function of time t or an observation period and / or a mileage of the vehicle (x-axis).

[0079] For example, a vehicle with four air springs can be assumed. The leakage rate v for the air spring(s) 100 at the front right Fr_Re, front left Fr_Li, rear right Hi_Re and rear left Hi_Li is shown. The (respective) leakage rate v can vary and, in particular, become larger or smaller. This can be reduced (at least partially) by smoothing. However, if an air spring 100 has a (larger) leak, this can be determined by a leakage rate limit value v_limit being exceeded, with an air spring 100 at the rear right of the vehicle Hi_Re (first) exceeding the leakage rate limit value v_limit, for example. The curve (of Hi_Re) can be designed to be increasing, but in particular it does not necessarily (strictly) increase monotonically (d).

[0080] Fig. 4 shows, by way of example, a height h over time t. The times t1, t2, t3 are shown. The solid line can represent an air spring with a leak, the height of which drops comparatively sharply (h2 < h1). The dashed line can represent the height profile of an intact air spring, the height h of which, for example, does not drop or does not drop sharply. By way of example, a (first) measurement 110 of a first height h1 can be carried out at a first measurement time, here at time t1. Furthermore, a (second) measurement 120 of a second height h2 can be carried out at a second measurement time, here at time t2. A measurement time interval Δt_mess can lie between t1 and t2, e.g. Δt_mess = [t1, t2] or Δt_mess = ]t1, t2[. It can be provided that a height adjustment-free time interval Δt12 is provided, in particular between the first time t1 and the second time t2.This can be designed identically to the measuring time interval Δt_mess. An actual height change Δh_ist can be calculated by determining 130, e.g. by subtracting Δh_ist = h1 - h2 or Δh_ist = h2 - h1. A height adjustment can be carried out (beginning) at t2 up to time t3 in order to preferably compensate the height of the air spring (continuous line) with leakage. The height of the air springs can be adjusted (e.g. to a zero level) and / or compensated, in particular after or through a height adjustment. For example, Δt_mess or Δt12 can be approximately 5 minutes. A leakage rate v can be calculated by dividing Δh_ist by Δt_mess or Δt12. In . Fig. 4, a first and / or second measurement 110, 120 can therefore be provided apart from or outside of an altitude adjustment (e.g. in an altitude adjustment-free time interval).

[0081] Fig. 5 shows (especially in reference to Fig. 4) By way of example, a height h over time t. The times t1, t2, t3 are shown. The solid line can represent an air spring with a leak, the height of which is dropping or has dropped particularly significantly. By adjusting the height, the first height h1 can be raised to a second height h2 (h2 > h1). The dashed line can represent the height profile of an intact air spring 100, the height of which, for example, does not drop or is not adjusted significantly. By way of example, a (first) measurement 110 of a first height h1 can be carried out at a first measurement time, here at time t2. Furthermore, a (second) measurement 120 of a second height h2 can be carried out at a second measurement time, here at time t3. A measuring time interval Δt_mess can be between t1 and t2, e.g. Δt_mess = [t1, t2] or Δt_mess = ]t1, t2[.It can be provided that a height adjustment-free time interval Δt12 is provided, in particular between the first time t1 and the second time t2. This can be designed identically to the measuring time interval Δt_mess. An actual height change Δh_ist can be calculated by determining 130, e.g. by subtracting Δh_ist = h1 - h2 or Δh_ist = h2 - h1. A height adjustment can be carried out (beginning) at t2 up to time t3, in order to preferably compensate the height of the air spring (solid line) with a leak. A time interval subject to height adjustment can therefore last from the second time t2 up to the third time t3. The height of the air springs can be adjusted (e.g. to a zero level) and / or compensated, in particular after or through a height adjustment. For example, Δt_mess or Δt12 can be about 5 minutes.A leakage velocity v can be calculated (again) by dividing Δh_actual by Δt_measured or Δt12. In . Fig. 5, a first and / or second measurement 110, 120 can therefore be provided during an altitude adjustment (e.g. in a time interval subject to altitude adjustment). List of reference symbols 10 Altitude sensor 100 air spring 110 measurements at a first measurement time 120 measurements at a second measurement time 130 Determining an actual elevation change 131 Calculate the difference between the second height and the first height 140 Detecting a Leak 142 Comparison between expected altitude change and actual altitude change 143 Calculating the difference between expected altitude change and actual altitude change 144 Determine that there is no leakage, 145 Detecting a Leak 150 Calculating a leakage velocity 151 Compare 152 Detecting a leakage above the leakage speed limit 153 Determine that there is no leak 200 vehicles ECU control unit CU computing unit MU storage unit h height h1 first height h2 second height h_grenz height limit t time t1, t2 first measurement time t2, t3 second measurement time t1 first time point t2 second time point t3 third time point Δt_mess measurement time interval Δt12 altitude adjustment-free time interval Δt23 altitude adjustment time interval v Leakage rate v_grenz leakage speed limit Δh_erw expected altitude change Δh_ist actual height change Fr_Li air spring front left Fr_Re air spring front right Hi_Li air spring rear left Hi_Re air spring rear right

Claims

[1] Method for detecting a leakage of at least one air spring (100) of a vehicle (200), the vehicle (200) comprising: - at least one air spring (100) comprising a height sensor (10), the method comprising - measuring (110), at a first measuring time (t1, t2), a first height (h1) of the air spring (100) by the height sensor (10), - measuring (120), at a second measuring time (t2, t3), a second height (h2) of the air spring (100) by the height sensor (10), wherein the second measuring time (t2, t3) has a measuring time interval (Δt_mess) to the first measuring time (t1, t2), wherein the measuring time interval (Δt_mess) has at least one height adjustment-free time interval (Δt12) or a height adjustment-dependent time interval (Δt23), - determining (130) an actual change in height (Δh_ist) as a function of the first height (h1) and the second height (h2), - Determining (140) a leakage of the at least one air spring (100) as a function of the actual height change (Δh_ist) and the first measuring time (t1, t2). [2] Method according to one of the preceding claims, characterized by that the determination (140) is carried out as a function of the altitude adjustment-free time interval (Δt12), wherein in particular the altitude adjustment-free time interval (Δt12) begins or ends with the first measuring time (t1, t2). [3] Method according to one of the preceding claims, characterized by , that the first measuring time (t1, t2) has a first time (t1) and the second measuring time (t2, t3) has a second time (t2), or, that the first measuring time (t1, t2) has a second time (t2) and the second measuring time (t2, t3) has a third time (t3). [4] Method according to one of the preceding claims, characterized bythat the determination (130) of an actual height change (Δh_ist) as a function of the first height (h1) and the second height (h2) is carried out by forming the difference (131) between the second height (h2) and the first height (h1). [5] Method according to one of the preceding claims, characterized by in that the first measuring time (t1, t2) comprises an end of a height adjustment, wherein a height adjustment is designed to adjust a height of the at least one air spring, for example to a zero level, and wherein preferably the second measuring time (t2, t3) has a second time (t2) at which preferably a height adjustment begins. [6] Method according to one of the preceding claims, characterized byin that the second measuring time (t2, t3) has a measuring time interval (Δt_mess) to the first measuring time (t1, t2), wherein the measuring time interval (Δt_mess) has at least one altitude adjustment-free time interval (Δt12), in particular from a first time (t1) to a second time (t2), and at least one altitude adjustment-related time interval (Δt23), in particular from a second time (t2) to a third time (t3), wherein in particular the second measuring time (t2, t3) has a third time (t3), which in particular has an end to an altitude adjustment. [7] Method according to one of the preceding claims, characterized by that the method is designed to be carried out during operation of the vehicle (200). [8] Method according to one of the preceding claims, characterized bythat the determination (140) comprises a comparison (142), in particular a difference formation (143), between an expected change in altitude (Δh_erw) and the actual change in altitude (Δh_ist), wherein in particular - a determination (144) that there is no leakage occurs if the comparison (142) shows no deviation or a deviation below a height limit value (h_limit) between the actual height change (Δh_actual) and the expected height change (Δh_expected), - a leak is detected (145) if the comparison (142) shows a deviation above a height limit value (h_grenz) between the actual height change (Δh_ist) and the expected height change (Δh_erw). [9] Method according to one of the preceding claims, characterized byin that the determination (140) comprises a calculation (150) of a leakage velocity (v), wherein in particular the leakage velocity (v) is calculated by dividing the actual height change (Δh_ist) by the measurement time interval (Δt_mess) or a height adjustment-free time interval (Δt12). [10] Method according to one of the preceding claims, characterized by that the determination (140) of a leakage of the at least one air spring (100) comprises a comparison (151), comprising - detecting (152) a leak if a leakage speed limit value (v_grenz) has been exceeded, in particular by a leakage speed (v), - determining (153) that there is no leakage if a leakage speed limit value (v_grenz) has not been exceeded, in particular if a leakage speed (v) is less than or equal to the leakage speed limit value (v_grenz). [11] Air spring (100) for a vehicle (200), wherein the air spring (100) is designed, in particular in cooperation with a vehicle (200), to implement the method according to one of the preceding claims. [12] A computer program product comprising instructions which, when the computer program product is executed by a computer, cause the computer to implement the method according to any one of the preceding claims. [13] Computer-readable data carrier in which instructions are stored which, when executed by a computer, cause the computer to carry out the method according to one of the preceding claims. [14] Control unit (ECU), comprising a computing unit (CU) and a memory unit (MU) in which instructions are stored which, when at least partially executed by the computing unit (CU), carry out a method according to one of the preceding claims. [15] Vehicle (200) comprising a control unit (ECU) according to the preceding claim and / or at least one air spring (100) according to one of the preceding claims.

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